Fix MT5 init (#12591)

src/transformers/models/mt5/__init__.py

@@ -29,24 +29,22 @@ from ...file_utils import (
 
 if is_sentencepiece_available():
     from ..t5.tokenization_t5 import T5Tokenizer
+else:
+    from ...utils.dummy_sentencepiece_objects import T5Tokenizer
 
-    MT5Tokenizer = T5Tokenizer
+MT5Tokenizer = T5Tokenizer
 
 if is_tokenizers_available():
     from ..t5.tokenization_t5_fast import T5TokenizerFast
+else:
+    from ...utils.dummy_tokenizers_objects import T5TokenizerFast
 
-    MT5TokenizerFast = T5TokenizerFast
+MT5TokenizerFast = T5TokenizerFast
 
 _import_structure = {
     "configuration_mt5": ["MT5Config"],
 }
 
-if is_sentencepiece_available():
-    _import_structure["."] = ["T5Tokenizer"]  # Fake to get the same objects in both side.
-
-if is_tokenizers_available():
-    _import_structure["."] = ["T5TokenizerFast"]  # Fake to get the same objects in both side.
-
 if is_torch_available():
     _import_structure["modeling_mt5"] = ["MT5EncoderModel", "MT5ForConditionalGeneration", "MT5Model"]
 
@@ -57,16 +55,6 @@ if is_tf_available():
 if TYPE_CHECKING:
     from .configuration_mt5 import MT5Config
 
-    if is_sentencepiece_available():
-        from ..t5.tokenization_t5 import T5Tokenizer
-
-        MT5Tokenizer = T5Tokenizer
-
-    if is_tokenizers_available():
-        from ..t5.tokenization_t5_fast import T5TokenizerFast
-
-        MT5TokenizerFast = T5TokenizerFast
-
     if is_torch_available():
         from .modeling_mt5 import MT5EncoderModel, MT5ForConditionalGeneration, MT5Model
 
@@ -76,20 +64,7 @@ if TYPE_CHECKING:
 else:
     import sys
 
-    class _MT5LazyModule(_LazyModule):
-        """
-        Module class that surfaces all objects but only performs associated imports when the objects are requested.
-        """
-
-        def __getattr__(self, name):
-            if name == "MT5Tokenizer":
-                return MT5Tokenizer
-            elif name == "MT5TokenizerFast":
-                return MT5TokenizerFast
-            else:
-                return super().__getattr__(name)
-
-    sys.modules[__name__] = _MT5LazyModule(
+    sys.modules[__name__] = _LazyModule(
         __name__,
         globals()["__file__"],
         _import_structure,